We have mapped 3 QTLsin he mouse which modulate response to
infection by L. major. These loci have been isolated onto
isogenic backgrounds, both susceptible and resistant. These
animals have a phenotype which is partway between that of the
resistant and susceptible parents. A compound congenic animal
has been bred with all three loci on both susceptible and
resistant backgrounds. These animals can be fully resistant or
susceptible, although the penetrance is not as complete as the
parental lines.

Dogma has it that the T cell helper responses are important
in determining outcome in this disease. We have measured the T
cell responses in our congenic animals and found that there is
no difference between the congenics and their backcross
parental strain indicating that the Th response is not playing
any role in these animals.

We have performed a microarray analysis on infected and
unifected macrophages (the host cell) on compound congenic
animals from both susceptible and resistant backgrounds. Among
many genes differing between these animals were genes involved
in wound healing. We therefore examined the wound healing
response in our congenic mice and found a considerable
difference. This difference was seen in both new wounds and in
the response to the leishmania lesion itself. We conclude
therefore that wound healing plays a major role in the host
response to cutaneous leishmaniasis.